1. Field of the Invention
The present invention relates to systems and methods for control of an internal combustion engine to provide vehicle deceleration closed-loop control when the accelerator pedal is fully released or closed.
2. Background Art
Control strategies for vehicles with internal combustion engines often use both closed-loop feedback control and open-loop control for various engine/vehicle functions and operating conditions. Closed-pedal operation of the engine while the vehicle is moving, i.e. when the driver fully releases the accelerator pedal, has traditionally been open-loop with the engine being returned to idle and the vehicle deceleration profile not actively controlled. As such, the vehicle speed/deceleration profile for closed-pedal operation changes as a function of various engine, vehicle, and ambient operating conditions such as engine pumping losses, driveline friction, road load, road grade, vehicle loading, wind speed and direction, etc. For example, if the driver is approaching another vehicle while climbing a hill and releases the accelerator pedal to reduce speed, the vehicle decelerates more rapidly than if the vehicle was descending a hill and the driver released the accelerator pedal.
The present inventors have recognized that a closed-pedal behavior that is less dependent on the operating environment may enhance drivability of the vehicle and that by controlling the closed-pedal deceleration it would be possible to calibrate the vehicle deceleration as a function of vehicle brand image and/or vehicle type, e.g. sports car vs. truck, taking into account the current operating environment, e.g. ambient temperature and pressure, vehicle load, road grade, on-road or off-road operation, etc.